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Fix a race condition in IPI handlers of save/drop fpstate, from OpenBSD. 

Reported and tested by martin@.
This commit is contained in:
nakayama 2008-03-17 23:54:03 +00:00
parent 33928e0f83
commit 0a332c0d29
2 changed files with 21 additions and 11 deletions
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26
sys/arch/sparc64/sparc64/locore.s
View File

@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.271 2008/03/17 04:04:00 nakayama Exp $ */
/* $NetBSD: locore.s,v 1.272 2008/03/17 23:54:03 nakayama Exp $ */
/*
* Copyright (c) 1996-2002 Eduardo Horvath
@ -9512,18 +9512,23 @@ Lkcerr:
/*
* IPI handler to store the current FPU state.
* void sparc64_ipi_save_fpstate(void *);
*
* On entry:
* %g2 = lwp
*/
ENTRY(sparc64_ipi_save_fpstate)
sethi %hi(FPLWP), %g1
LDPTR [%g1 + %lo(FPLWP)], %g3
cmp %g3, %g2
bne,pn CCCR, 7f ! skip if fplwp != %g2
LDPTR [%g3 + L_FPSTATE], %g3
mov CTX_SECONDARY, %g5
ldxa [%g5] ASI_DMMU, %g6
membar #LoadStore
stxa %g0, [%g5] ASI_DMMU
membar #Sync
sethi %hi(FPLWP), %g1
LDPTR [%g1 + %lo(FPLWP)], %g3
LDPTR [%g3 + L_FPSTATE], %g3
rdpr %pstate, %g2 ! enable FP before we begin
rd %fprs, %g5
wr %g0, FPRS_FEF, %fprs
@ -9564,6 +9569,7 @@ ENTRY(sparc64_ipi_save_fpstate)
STPTR %g0, [%g1 + %lo(FPLWP)] ! fplwp = NULL
stxa %g6, [%g5] ASI_DMMU
membar #Sync
7:
IPIEVC_INC(IPI_EVCNT_FPU_SYNCH,%g2,%g3)
ba,a ret_from_intr_vector
nop
@ -9631,16 +9637,20 @@ ENTRY(sparc64_ipi_save_fpstate)
/*
* IPI handler to drop the current FPU state.
* void sparc64_ipi_drop_fpstate(void *);
*
* On entry:
* %g2 = lwp
*/
ENTRY(sparc64_ipi_drop_fpstate)
rdpr %pstate, %g1
wr %g0, FPRS_FEF, %fprs
or %g1, PSTATE_PEF, %g1
wrpr %g1, 0, %pstate
sethi %hi(FPLWP), %g1
set FPLWP, %g1
CASPTR [%g1] ASI_N, %g2, %g0 ! fplwp = NULL if fplwp == %g2
IPIEVC_INC(IPI_EVCNT_FPU_FLUSH,%g2,%g3)
ba ret_from_intr_vector
STPTR %g0, [%g1 + %lo(FPLWP)] ! fplwp = NULL
ba,a ret_from_intr_vector
nop
#endif
/*

6
sys/arch/sparc64/sparc64/vm_machdep.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vm_machdep.c,v 1.79 2008/03/14 15:39:18 nakayama Exp $ */
/* $NetBSD: vm_machdep.c,v 1.80 2008/03/17 23:54:03 nakayama Exp $ */
/*
* Copyright (c) 1996-2002 Eduardo Horvath. All rights reserved.
@ -50,7 +50,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.79 2008/03/14 15:39:18 nakayama Exp $");
__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.80 2008/03/17 23:54:03 nakayama Exp $");
#include "opt_multiprocessor.h"
#include "opt_coredump.h"
@ -334,7 +334,7 @@ fpusave_lwp(struct lwp *l, bool save)
continue;
sparc64_send_ipi(ci->ci_cpuid, save ?
sparc64_ipi_save_fpstate :
sparc64_ipi_drop_fpstate, 0, 0);
sparc64_ipi_drop_fpstate, (uintptr_t)l, 0);
spincount = 0;
while (ci->ci_fplwp == l) {